Breech block and firing pin assembly for small arms



w. B. RUGER 2,624,969

BREECH BLOCK AND FIRING PIN ASSEMBLY FOR SMALL ARMS Jan. 13, 1953 Filed June 28, 1950 FIG.- 2

ATTORNEYS Patented Jan. 13, 1953 BREECH BLOCK AND FIRING PIN ASSEMBLY FOR SMALL ARMS William B. Ruger, Westport, Conn assignor to Sturm, Ruger & Co., Inc., Southport, Conn, a corporation of Connecticut Application June 28, 1950, Serial No. 170,753

2 Claims. 1

This invention relates to small arms and has for "its object the provision of an improved breech block and firing pin assembly for such arms. My invention is primarily applicable to reciprocable breech blocks or bolts for rifles, pistols, and the like, and is characterized by simplicity of construction and assembly with resulting low production cost.

This invention provides a firing pin of unusual durability and one that is particularly well adapted to the requirements of rimfire firearms. InQthis class of firearms, it is essential that the forward motion of the firing pin be arrested as soon as it protrudes a sufficient distance from the face of the breech bolt to insure reliable ignition of the cartridge because, if it is permitted to move too far forward, the point of the firing pin will eventually do irreparable damage to the breech of the barrel when the gun is snapped on an empty chamber.

The means for arresting this forward motion of the firing pin must be adequate to absorb the firing pin blow without upsetting or wear under a great number of cycles because, in the normal use of a firearm, it is frequently desirable, or necessary, to pull the trigger when the gun is not loaded. If the arresting means are inadequate, they will gradually begin to wear and upset, thereby permitting a continual increase in the distance that the point of the firing pin protrudes from the face of the breech bolt and, therefore, although the forward motion of the firing pin may be properly limited when the gun is new, after a certain amount of usage, the firingpin will begin to increase its protrusion and eventually damage the barrel.

My invention provides unusually effective means for arresting the forward motion of the firing pin and, at the same time, these means introduce a minimum of undesirable stresses in the firing-pin itself. n

The breech block firing pin combination of my invention comprises a breech block having a longitudinal slot in which the firing pin is inserted and secured with limited slidable movement, and a rebound spring in the slot under the firing pm. One of the important features of the invention is that the slot opens through to the exterior of the breech block and extends into hold the firing pin in slidable contact with the bearing surfaces. Another important feature of the invention is that the rebound spring and its associated follower bar are merely placed in the longitudinal slot, one end of the spring bearing against a shoulder of the firing pin and the follower bar bearing on the breech block.

In one of its advantageous embodiments, the invention comprises a breech block for blowback actions having a return spring and follower rod. In this adaptation of the invention, I widen the longitudinal slot above the location of the firing pin to receive the return spring and its follower rod. I prefer also to form a transverse slot in the breech block and insert therein a loosely fitting base plate having a hole for the follower rod and a bearing surface for the spring. The base plate is secured in position by the wall of the receiver in which the breech block is inserted.

In a more complete embodiment, my invention includes in the combination an extractor of the type commonly used on autoloading pistols comprising an extractor member and a spring pressed key-bar which operatively secures the extractor member in position. The said extractor member requires a longitudinal hole for the spring and key-bar and a transverse connecting hole for an extension of the extractor member. In accordance with my invention, I merely extend this transverse hole to intersect the longitudinal slot for the firing pin and thereby provide a base or shoulder for the follower bar of the rebound spring.

The invention has the advantages of great simplicity with simple shapes serving dual pur poses and formed in eificient production opera tions; The firing pin, for example, can be formed by blanking steel strip stock.

These and other objects of the invention will be better understood after considering the following discussion taken in conjunction with the accompanying drawings, in which:

Fig. l is a plan View of a breech block and firing pin combination of the invention;

Fig. 2 is a vertical sectional View of the breech Fig. 5 is an enlarged sectional view at 55 of Fi 2.

The drawings illustrate, by way of example, a

breech block I of the blowback type for .22 caliber rimfire cartridges. The breech block is formed of a single piece of steel of more or less cylindrical cross-sectional shape and having a hand operating knob 2 at the rear end. The block has a vertical cut 3 for the swing of the hammer (not shown) and by means of which the block is guided in its travel on the vertically disposed blocking post 4. It is to be understood that the knob 2, slot 3 and post 4 are shown merely to illustrate one complete form of breech block and are not essential parts of this invention. The block is sliced off horizontally providing the recess 5 for reasons that will appear presently.

The breech block has an open longitudinal slot 6 formed as with a milling machine, the uppermost portion of which is relatively wide (Fig. 3) to receive the action spring 1 and its follower rod 8, and a relatively narrow under portion to receive the fiat firing pin 9. The slot is so formed as to provide a front bearing surface I2 for the forward end of the firing pin. The firing pin is preferably blanked from fiat steel strip stock and has a pyramidal shaped cartridge-striking end l4 and a chamfered end which is struck by the hammer. The hole 16 in the form of an elongated guide slot coincides with the hole I! in the breech block into which the cross pin [8 is inserted to hold the firing pin in slidable engagement, thus preventing up and down movement of the rear end of the firing pin.

The forward end of the breech block has a transverse slot I9 into which is inserted the arcuate plate 29 having a hole 2| in which the follower rod 8 is inserted and the spring 1 accordingly bears against the plate. The follower rod, of course, slides through the hole 2| as the block travels rearward. When the breech block is mounted in an appropriately shaped receiver recess (not shown), the inner wall thereof holds the plate 20 in position and this plate holds the front end of the firing pin down in contact with surface [2. The rear end of rod 8 has a slit in which the plate 22 is crimped and as the breech block reciprocates the fiat surface of recess 5 slides under the plate. The return spring bears against the plate 22 and presses the plate together with the rod against post 4.

With reference to Figs. 3 and 4, it will be seen that the breech block has an undercut 25 for clearing the magazine (not shown) and the head end has a cartridge-receiving recess 26 into which the firing pin projects.

The extractor is a type well known comprising an extractor member 21 mounted in the slot 28, an operating spring 29, and bearing rod or keybar 30 in the longitudinal hole 32. The lateral hole 33 receives the projecting lug 45 by means of which the extractor is held in position by the key-bar 30. In accordance with my invention, I extend the hole 33 to a point where it intersects the narrow portion of the slot 6 (Figs. 2 and 5).

As best shown in Fig. 2, the slot 6 has an arcuate bottom 6' being a shape readily obtained by conventional milling cutters in which the depending shoulder 34 of the firing pin projects. The rebound spring 35 and its follower bar 36 ar mounted in the slot under the firing pin with the spring against the shoulder 34 and the end of the bar 35 against the wall of hole 33, thereby providing a convenient support for the spring.

The manufacturing advantages of the improved breech block of the invention will be appreciated when it is understood that it can be made with a relatively few number of very simple machine operations.

In addition to manufacturing advantages, this invention provides an unusually effective means of arresting the forward motion of the firing pin. As can be readily seen, this is accomplished by the cross pin 18 which engages the rear portion of the elongated slot i6. Inasmuch as pin I8 also guides the firing pin in a vertical plane, it will be apparent that the firing pin is free to assume a good seating between the pin l8 and the rear portion of slot I6 without constraint from any adjacent surfaces and without sidewise thrusts being imposed upon the firing pin.

In many firing pin arrangements, the means for arresting the forward motion are located to one side of the principal mass of the firing pin and, for that reason, introduce turning moments which are likely to strain the firing pin to some extent whenever the gun is fired and particularly when the firing pin is struck by the hammer when there is no cartridge in the chamber as, in this case, the firing pin is deprived of the crushing effect of driving into the soft brass rim of the cartridge.

I claim:

1. The improved breech block firing pin combination for small arms which comprises a breech block having a cartridge recess, a longitudinal slot in the breech block milled from the exterior which opens into the cartridge recess of the breech block, said slot having a relatively wide upper portion for a return spring and follower rod and a relatively narrow under part for the firing pin, a firing pin of fiat strip stock in the relatively narrow part of the slot, a transverse slot in the forward end of the breech block, an arcuate plate mounted in the transverse slot which holds the forward end of the firing pin down, and a cross pin inserted through coincident holes in the breech block and firing pin to arrest the forward movement of the firing pin.

2. The improved breech block firing pin combination for small arms which comp-rises a longitudinal slot in the breech block, a firing pin inserted in the slot, means for limiting the movement or" the firing pin and securing it in the slot, a rebound spring and follower bar therefor mounted in the slot under the firing pin, said breech block having intersecting longitudinal and transverse holes for an extractor, the transverse hole intersecting said slot, the follower bar for the rebound spring having one end bearing against the wall of the transverse hole and the other against the spring.

WILLIAM B. RUGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,105,416 Fyrberg July 28, 1914 1,294,506 Martin Feb. 18, 1919 2,248,445 Wilson July 8, 1941 2,296,242 Brewer Sept. 22, 1942 2,310,238 Horsrud Feb. 9 1943' 2,490,474 Roemer Dec. 6 1949 

